Is PDAF a HOAX?

I find the NEX 6 to be an upgrade to the 5N focusing. The 5N in lower light would pick things in the far corners of the frame and 20 feet behind my actual subjects, even when the subject was filling most of the frame.

I am not having this issue with the NeX6. It focuses on what I want it to. It does seem more accurate and faster. But it can still be improved quite a bit.